Ether, benzyl ethyl preparation

Write equations describing two different ways in which benzyl ethyl ether could be prepared by a Williamson ether synthesis J... 

Methyl, ethyl, and benzyl ethers have been prepared in the presence of tetraethylammonium fluoride as a Lewis base (alkyl halide, DME, 20°, 3 h, 60-85% yields). ... 

Acetals of aldehydes are usually stable to lithium aluminum hydride but are reduced to ethers with alane prepared in situ from lithium aluminum hydride and aluminum chloride in ether. Butyraldehyde diethyl acetal gave 47% yield of butyl ethyl ether, and benzaldehyde dimethyl acetal and diethyl acetal afforded benzyl methyl ether and benzyl ethyl ether in 88% and 73% yields, respectively [792]. 

How wovki you prepare th foltowing ethers Vse whichever method you think more npproi>riiiio, the Williamaon synthaeis or the ulknxymcrcuran n reacUon (a> Butyl cyelohexy) ether (b) Benzyl ethyl ther iC Hg CH OCHjCHi> tc) Urt B > y iof but> l ether id) Tetrahydrofuran... 

Aromatic and aliphatic amino ethers have been synthesized by this method. An example of the formation of a cyano ether is the preparation of p-cyano benzyl methyl ether from the substituted benzyl bromide and sodium methoxide (84%). Also, certain aryloxyacetonitriles, AtOCHjCN, are made by the condensation of chloroacetonitrile with sodium phenoxides in a solution of methyl ethyl ketone containing a small amount of sodium iodide (70-80%). Aromatic nitro ethers, like o- and p-nitrodiphenyl ether, have been prepared by the Ullmann procedure (84%). The synthesis of alkyl p-nitrophenyl ethers has also been accomplished with good yields (55-92%). ... 

Several methoxy-substituted benzyl etbers have been prepared and used as protective groups. Tbeir utility lies in tbe fact that they are more readily cleaved oxidatively than tbe unsubstituted benzyl etbers. These etbers are not stable to metbyl(trifluorom ethyl)dioxirane, which oxidizes the aromatic ring. The relatedp-(dodecyloxy)benzyl ether has been prepared to facilitate chromatographic purification of carbohydrates on Ci8 silica gel. The table below gives the relative rates of cleavage with dichloro-dicyanoquinone (DDQ). ... 

Benzyl Ethyl Ether, (Etkoxymethyt)benzime. C,-UqO mol wt 136.19. C 79.37%, H 8.88%. O 11.75%. CUHjCHjOCjHj. Preparation from sodium etboxide and benzyl bromide Letsinger, Pollart, J. Am, Chem. Soc. 78, 6079 (1956) by reduction of benzaldehyde diethyl acetal with LlAHl,. AIC1Eliet, Rerick, J. Org. Chem. 23, 1088 (1958). 

Benzylic halogenation provides a useful way to introduce a leaving group when a leaving group may be needed for subsequent nucleophilic substitution or elimination reactions. For example, if we wished to synthesize benzyl ethyl ether from toluene, benzyl bromide could be prepared from toluene as above, and then benzyl bromide could be allowed to react with sodium ethoxide as follows. 

By use of a modification of the well-known Williamson synthesis it is possible to prepare a number of cellulose ethers. Of these materials ethyl cellulose has found a small limited applieation as a moulding material and somewhat greater use for surfaee eoatings. The now obsolete benzyl cellulose was used prior to World War II as a moulding material whilst methyl eellulose, hyroxyethyl eellulose and sodium earboxymethyl eellulose are useful water-soluble polymers. 

Both methyltriethylphosphonium fluoride and methyltributylphospho-nium fluoride have been prepared The latter generates benzyl fluoride from benzyl chloride in 80% yield and ethyl fluoroacetate from ethyl bromoacetate in 53% yield Methyltnbutylphosphonium fluoride converts 1-bromododecane to a 50 50 mixture of 1-fluorododecane and 1-dodecene Methyltnbutylphosphonium fluoride also quantitatively forms styrene from 1-bromo-1-phenylethane [26] Methyl-tnbutylphosphonium fluonde is the reagent of choice for the conversion of N,N dimethylchloroacetamide to its fluoride, but it is not able to convert chloro-acetonitnle to fluoroacetomtrile Methyltnbutylphosphonium fluoride changes chloromethyl octyl ether to the crude fluoromethyl ether in 66% yield The stereoselectivity of methyltnbutylphosphonium fluoride is illustrated by the reac tions of the 2-tert-butyl-3-chlorooxiranes [27] (Table 2)... 

A solution of sodium ethylate is prepared from 60 g. (2.6 gram atoms) of clean sodium and 700 cc. of absolute alcohol (Note 1) in a 2-1. round-bottomed flask, equipped with a reflux condenser. To the hot solution is added a mixture of 234 g. (2 moles) of pure benzyl cyanide (Note 2) and 264 g. (3 moles) of dry ethyl acetate (Note 3). The mixture is thoroughly shaken, the condenser closed with a calcium chloride tube, and the solution heated on the steam bath for two hours before standing overnight (Note 4). The next morning the mixture is stirred with a wooden rod to break lumps, cooled in a freezing mixture to — io°, and kept at this temperature for two hours. The sodium salt is collected on a 6-in. Buchner funnel and washed four times on the funnel with 250-cc. portions of ether. The filter cake is practically colorless and corresponds to 250-275 g. of dry sodium salt, or 69-76 per cent of the calculated amount. The combined filtrates are placed in the freezing mixture until they can be worked up as indicated below. 

Preparation of 4-(l-phenvlethvloxvl-stvrene. This benzylic ether of p-hydroxystyrene was prepared by a Wittig reaction on the precursor aldehyde as described above. The final product was obtained in 73% yield after purification by preparative HPLC using 5% ethyl acetate in hexane as eluent. The product had analytical characteristics in agreement with the proposed structure. 

Aromatic Compounds.—A number of 2,3-dihydroxyoestra-l,3,5(10)-trienes have been prepared from the corresponding 2-amino-3-hydroxy-compounds using a novel inverse oxidation procedure followed by reduction with KI. Addition of the substrate to sodium metaperiodate in high dilution ensures no coupling with the intermediate quinonimines. 2-Bromo-oestradiol was readily converted into 2-methoxyoestradiol by treatment with NaOMe-MeOH-DMF-CuI. Novel preparations of the biologically interesting 11/3-methyl- and 11/3-ethyl-oestradiol have been reported in full. The key intermediates were the 11-oxo-oestradiol 3-benzyl ether (82) and its 9/3-epimer (83). The latter was derived from the 9,H-epoxides (81) by treatment with KOH followed by benzylation. The thermodynamically unstable 9a-epimer (82) was prepared from the 9j8-epimer (83) by... 

The preparatively useful and simple N-alkylation procedure that utilizes a combination of carboxylic acid and sodium borohydride has been applied to carbazole giving an efficient 9-ethylation. Also of preparative importance is the use of thallous ethoxide as base in dimethylformamide-ether 9-methyl-, 9-ethyl-, n-propyl-, n-butyl-, benzyl-, and n-allylcarbazoles were efficiently produced, as well as 9,9 -dicarbazolylalkanes using C3, C4, and Cg dihalides. 2-Acetyl- and 2-vinylcarbazole were also efficiently 9-ethylated by this route. Another more recent approach to N-alkylation of carbazole utilizes potassium terf-butoxide in the presence of a catalytic quantity of 18-crown-6 9-methylcarbazole was prepared in high yield. ... 

Meyers and Shimano discovered the unusual deprotonation behavior of ethoxy-vinyllithium-HMPA complex (EVL-HMPA) for the deprotonation of the trans-oxazoline 366 and the cw-oxazoline 367. The EVL-HMPA complex is prepared by deprotonation of ethyl vinyl ether with ferf-butyllithium in THE followed by addition of HMPA. Reaction of the frani-oxazoline 366 with both the EVL-HMPA complex and conventional alkyllithium reagents (RLi) resulted in deprotonation at the benzylic 5-position. In contrast, deprotonation of 367 occurred at the 4-position with an alkyllithium reagent RLi, whereas benzylic deprotonation predominated with the EVL-HMPA complex (Scheme 8.117). ° The authors proposed that EVL-HMPA complexes with the 5-phenyl substituent prior to deprotonation. 

A series of pyrido[2,3-rf pyrimidine-2,4-diones bearing substituents at C-5 and/or C-6 were synthesized using palladium-catalyzed coupling of uracil derivative 417 with vinyl substrates or allyl ethers to give the regioisomeric mixtures of 418/419 and 420/421, respectively. The ratio of the isomeric structures was dependent on the substituent R. In the case of the reaction with -butyl vinyl ether, only the product 419 was obtained. However, the reactions with acrylonitrile, ethyl acrylate, 2-trifluoromethylstyrene, and 3-nitrostyrene afforded only 418. Also, reaction with allyl phenyl ether gave only 420. The key intermediate 417 was prepared by the reaction of 6-amino-l-methyluracil with DMF-DMA (DMA = dimethylacetamide), followed by N-benzylation with benzyl chloride and vinyl iodination with iV-iodosuccinimide (NIS) (Scheme 15) <2001BML611>. 

A mixture of 349 mg (1 mmol) of (3S.6S,7aS)-6-benzyl-tetrahydro-3-isopropyl-6-methyl-7a-phenylpyrro-lo[2.1 -A oxazol-5(6//)-one (9, R2 = f-Pr R4 = CH3) and 10 mL of 48% aq hydrobromic acid is heated at reflux for 24 h. After cooling to r.t., the solution is diluted with water and extracted with three portions of ethyl acetate. The combined extract is dried over anhyd Na2S04. filtered and concentrated in vacuo, and the residue is dissolved in diethyl ether. The ethereal solution is treated with excess diazomethane in diethyl ether, and the solution is filtered and concentrated. The residue is purified by preparative TLC and distilled bulb-to-bulb to give a colorless oil yield 233 mg (85%) 100% ee bp 120sC/0.07 Torr [a]D +12.8 (c = 1.2. CHC13). 

The present procedure is the best way of preparing aliphatic isocyanides boiling above ethyl isocyanide. It has been applied to the synthesis of the following isocyanides 6 isopropyl (38%), -butyl (61%), te -butyl (68%), and benzyl (56%). In preparing isopropyl isocyanide or teri-butyl isocyanide, the petroleum ether should be of boiling point 30-35°, as otherwise it is difficult to separate these low-boiling isocyanides in the indicated yield, and,... 

Many other ethers of carbohydrates have been prepared and described among these the more common additional ones are the following ethyl, benzyl, hydroxymethyl, hydroxyethyl, allyl, and cyanoethyl ethers. In the vast majority of the cases complete or nearly complete substitution of the hydroxyl groups was effected. In other instances partial substitution was obtained, but often little or no information was supplied concerning the location of substituents. Investigations of these types will be mentioned briefly, in order mainly to indicate the extent of the information that is available. 

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